Following the events of September 11, 2001, the responsibilities, operations and numbers of the U.S. Federal Air Marshal Service (FAMS) wer e greatly expanded. With this expansion, new critical research and te chnology needs were identified, including the need for air to ground telecommunications capabilities. To address this need, the FAMS has cr eated a working group to develop, deploy and enhance aviation communi cations with respect to security and law enforcement. This paper presents the working group's progress to date in generating a FAMS air-gro und communications roadmap identifying expected communications servic es, technology maturity, and technology gaps over a timeline. The paper includes a communications preliminary requirements summary and syst em performance characteristics needed to meet identified operational needs. The system engineering process utilized is presented beginning with the identification of users, their operational needs and relevant constraints. The operational needs are translated to desired airbor ne communications services. System technical performance requirements associated with the identified services are summarized. In addition, notional communications architectures addressing the requirements are presented. Finally, future plans to identify and assess potential ca ndidate systems and their associated technical architectures, gaps and barriers to implementation are discussed. The paper addresses the cu rrent, near term (within 5 years) and far term (10 years) timeframes for such an airborne communications system.